Ten ineffective interventions to prevent ventilator-associated pneumonia

Baseline Characteristics of Bronchial Secretions and Bronchoalveolar Lavage Fluid in Patients with Ventilator-Associated Pneumonia

Mechanically ventilated (MV) patients often develop ventilator-associated pneumonia (VAP) with increased mortality risk, especially in VAP caused by multidrug-resistant (MDR) microorganisms. We evaluated MV patients and monitored VAP presentation, microbiologically confirmed. The patients underwent bronchoalveolar lavage (BAL) and blind bronchial aspiration (AC) at baseline. Systematic bronchial secretion and radiologic assessments were performed daily. The patients were classified as MDR-VAP, non-MDR-VAP, or non-VAP. The APACHE II and SOFA scores, microbiology, inflammatory markers, respiratory system characteristics, and ventilator settings were evaluated. BAL and AC were assessed for total protein levels, cellular number and profile, and IL-1β and TNF-α levels. Of the VAP patients, 46.1% presented with MDR-VAP due to Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, or Stenotrophomonas maltophilia, and 53.8%-with non-MDR-VAP. The VAP patients had higher APACHE II scores and airway pressure but a lower baseline PO2/FIO2 compared to the non-VAP patients, while PO2/FIO2 was increased in MDR-VAP compared to non-MDR-VAP. BAL protein, IL-1β, and cellular levels were increased in VAP vs. non-VAP and in non-MDR-VAP compared to MDR-VAP. Macrophages and polymorphonuclears were 34.36% and 23.76% in VAP, statistically significant increased compared to non-VAP. Their percentages were also increased in non-MDR-VAP compared to MDR-VAP. These differences imply a different immunological profile in non-MDR-VAP patients. In conclusion, MDR-VAP patients may present significant differences in baseline clinical characteristics and molecular biomarkers, which may help in prompt diagnosis and an improved therapeutic approach.

Aerosolized Antibiotics to Manage Ventilator-Associated Infections: A Comprehensive Review

BACKGROUND

Ventilator-associated lower respiratory tract infectious complications in critically ill patients cover a wide spectrum of one disease process (respiratory infection), initiating from tracheal tube and/or tracheobronchial colonization, to ventilator associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). VAP occurence has been associated with increased intensive care unit (ICU) morbidity (ventilator days, as well as length of ICU and hospital stay) and ICU mortality. Therefore, treatments that aim at VAP/VAT incidence reduction are a high priority.

AIM

The aim of the present review is to discuss the current literature concerning two major aspects: (a) can aerosolized antibiotics (AA) administered in a pre-emptive way prevent the occurrence of ventilator-associated infections? and (b) can VAT treatment with aerosolized avert the potential evolution to VAP?

RESULTS

There were identified eight studies that provided data on the use of aerosolized antibiotics for the prevention of VAT/VAP. Most of them report favorable data on reducing the colonisation rate and the progression to VAP/VAT. Another four studies dealt with the treatment of VAT/VAP. The results support the decrease in the incidence to VAP transition and/or the improvement in signs and symptoms of VAP. Moreover, there are concise reports on higher cure rates and microbiological eradication in patients treated with aerosolized antibiotics. Yet, differences in the delivery modality adopted and resistance emergence issues preclude the generalisability of the results.

CONCLUSION

Aerosolized antibiotic therapy can be used to manage ventilator-associated infections, especially those with difficult to treat resistance. The limited clinical data raise the need for large randomized controlled trials to confirm the benefits of AA and to evaluate the impact on antibiotic selection pressure.

Risk factors of ventilator-associated pneumonia in elderly patients receiving mechanical ventilation

Purpose: The aim of this study was to verify the potential risk factors of ventilator-associated pneumonia (VAP) in elderly Chinese patients receiving mechanical ventilation (MV). The secondary aim of this study was to present logistical regression prediction models of VAP occurrence in elderly Chinese patients receiving MV. Methods: Patients (aged 80 years or above) receiving MV for ≥48 h were enrolled from the Chinese People's Liberation Army (PLA) General Hospital from January 2011 to December 2015. A chi-squared test and Mann-Whitney U-test were used to compare the data between participants with VAP and without VAP. Univariate logistic regression models were performed to explore the relationship between risk factors and VAP. Results: A total of 901 patients were included in the study, of which 156 were diagnosed as VAP (17.3%). The incidence density of VAP was 4.25/1,000 ventilator days. Logistic regression analysis showed that the independent risk factors for elderly patients with VAP were COPD (OR =1.526, P < 0.05), intensive care unit (ICU) admission (OR=1.947, P < 0.01), the MV methods (P < 0.023), the number of antibiotics administered (OR=4.947, P < 0.01), the number of central venous catheters (OR=1.809, P < 0.05), the duration of indwelling urinary catheter (OR=1.805, P < 0.01) and the use of corticosteroids prior to MV (OR=1.618, P < 0.05). Logistic regression prediction model of VAP occurrence in the Chinese elderly patients with mechanical ventilation:L o g i t   P = - 6 . 468 + 0 . 423 X 1 + 0 . 666 X 2 + 0 . 871 X 3 + - 0 . 501 X 5 + 0 . 122 X 6 + 0 . 593 X 7 + 0 . 590 X 8 + 1 . 599 X 9 . Conclusion: VAP occurrence is associated with a variety of controllable factors including the MV methods and the number of antibiotics administered. A model was established to predict VAP occurrence so that high-risk patients could be identified as early as possible.

Impact of a multifaceted prevention program on ventilator-associated pneumonia including selective oropharyngeal decontamination

PURPOSE

We describe the impact of a multifaceted program for decreasing ventilator-associated pneumonia (VAP) after implementing nine preventive measures, including selective oropharyngeal decontamination (SOD).

METHODS

We compared VAP rates during an 8-month pre-intervention period, a 12-month intervention period, and an 11-month post-intervention period in a cohort of patients who received mechanical ventilation (MV) for > 48 h. The primary objective was to assess the effect on first VAP occurrence, using a Cox cause-specific proportional hazards model. Secondary objectives included the impact on emergence of antimicrobial resistance, antibiotic consumption, duration of MV, and ICU mortality.

RESULTS

Pre-intervention, intervention and post-intervention VAP rates were 24.0, 11.0 and 3.9 VAP episodes per 1000 ventilation-days, respectively. VAP rates decreased by 56% [hazard ratio (HR) 0.44, 95% CI 0.29-0.65; P < 0.001] in the intervention and by 85% (HR 0.15, 95% CI 0.08-0.27; P < 0.001) in the post-intervention periods. During the intervention period, VAP rates decreased by 42% (HR 0.58, 95% CI 0.38-0.87; P < 0.001) after implementation of eight preventive measures without SOD, and by 70% after adding SOD (HR 0.30, 95% CI 0.13-0.72; P < 0.001) compared to the pre-intervention period. The incidence density of intrinsically resistant bacteria (to colistin or tobramycin) did not increase. We documented a significant reduction of days of therapy per 1000 patient-days of broad-spectrum antibiotic used to treat lower respiratory tract infection (P < 0.028), median duration of MV (from 7.1 to 6.4 days; P < 0.003) and ICU mortality (from 16.2 to 13.5%; P < 0.049) for patients ventilated > 48 h between the pre- and post-intervention periods.

CONCLUSIONS

Our preventive program produced a sustained decrease in VAP incidence. SOD provides an additive value.

Airway microbiome research: a modern perspective on surveillance cultures?

The incidence of ventilator-associated pneumonia (VAP) is estimated to be around 10% in a high-risk population. Over the last decade, major improvements have been made in the prevention of VAP, with great cost-effectiveness. However, we still do not understand the exact pathogenesis of VAP. A better understanding might explain why some patients develop ventilator-associated tracheobronchitis, while others develop VAP even though they are infected with the same types of pathogens. Microbiome research has been a hot topic in translational medicine over the past decade. Slowly, microbiome research has also been introduced to the intensive care setting. One of the areas where it may influence our pathophysiological considerations is in VAP. The adapted island has been proposed for the colonization and infection of the respiratory tract. In this model, not only the immigration of bacteria into the lung is important, but elimination and regional growth factors are of equal significance. The importance of these factors can be supported by epidemiological studies. Several small observational studies on the development of the pulmonary microbiome during mechanical ventilation also support this theory. We speculate on the consequences of the newest insights in microbiome research on the prevention and targeted treatment of VAP. We conclude that there is still a strong need for more in-depth analyses of the changes in the microbial composition of the pulmonary microbiome during mechanical ventilation and with the development of VAP.